Of 36 counties in the state, Union County is 17th in terms of its size (2,038 square miles). Union County is in Eastern Oregon. Recent listings of riverfront homes and property for sale in Oregon's Union County totals almost 2,000 acres and a combined market value of $10 million. The most common type of land for sale by combined acreage in Union County is house. Browse all waterfront property for sale in Union County on the Land Network to find the marina, lakefront and other recreational property that meets your needs, from waterside land perfect as a retirement investment to existing residential waterfront land and property for hunting, fishing and other outdoor-recreation pursuits! The most common type of land for sale by combined acreage in Union County is house.